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Mikotoksini so nizkomolekularni sekundarni metaboliti plesni, ki so toksični za človeka. Mikotoksini spadajo med najnevarnejše v živilih prisotne naravne kontaminante, saj lahko povečajo verjetnost za razna obolenja, kot so rak na jetrih in nastanek tumorjev, hkrati pa tudi oslabijo delovanje imunskega sistema. V nekaterih živilih je določena največja dovoljena koncentracija patulina, ohratoksina A in aflatoksinov (AFB1, AFB2, AFG1 in AFG2). Mikotoksini najpogosteje kontaminirajo predvsem žita in oreščke. Ker je sadje zaradi visoke vsebnosti hranljivih snovi, predvsem enostavnih ogljikovih hidratov ter visoke vodne aktivnosti, ugoden medij za rast plesni in posledično lahko tudi sintezo mikotoksinov, sem se v diplomskem delu osredotočila na raziskovanje kontaminiranosti fig, grozdja in jabolk z mikotoksini. Plesni pogosto okužijo tudi poškodovano sadje, ki je zaradi poškodb še bolj dovzetno za okužbe. V figah, grozdju in jabolkih so najpogosteje prisotni mikotoksini, ki jih proizvajajo plesni rodov Penicillium in Aspergillus. V svežih figah, so v največ primerih prisotni aflatoksini, v grozdju ohratoksin A, v jabolkih pa patulin. Ker se med procesi predelave sadja, vsebnost mikotoksinov ne zmanjša, so lahko prisotni tudi v končnih izdelkih, kot so suhe fige, vino, rozine, jabolčni sok ter kis. Mycotoxins are secondary metabolites with low molecular weight, which are toxic to humans. They belong to the most dangerous contaminants which can be found in food, because of their impact on development of liver cancer, growth of tumours and affect on immune system. The maximum allowable contents of patulin, ochratoxin A and aflatoxins (AFB1, AFB2, AFG1 and AFG3) are regulated in certain food. Mycotoxins are most often present in cereals and nuts. Because of high carbohydrate content and high water activity, fruits are also susceptible for fungi growth and consequente mycotoxin production. Mechanically damaged fruits are even more susceptible to the fungi infections. In this diploma thesis I emphasised the presence of mycotoxins in figs, grapes and apples. Mycotoxins which are present in figs, grapes and apples are often produced by different species of Aspergillus and Penicillium. Fresh figs are often contaminated by aflatoxins, grapes with ochratoxin A and apples with patulin. Since the mycotoxin content is usually not reduced during processing, mycotoxins can be present in final products, such as dried figs, wine, raisins, apple juice and vinegar. |
